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Gonzalez-Perez P, D'Ambrosio ES, Picher-Martel V, Chuang K, David WS, Amato AA. Parent-of-Origin Effect on the Age at Symptom Onset in Myotonic Dystrophy Type 2. Neurol Genet 2023; 9:e200073. [PMID: 37123986 PMCID: PMC10136683 DOI: 10.1212/nxg.0000000000200073] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Accepted: 03/02/2023] [Indexed: 05/02/2023]
Abstract
Background and Objectives The existence of clinical anticipation, congenital form, and parent-of-origin effect in myotonic dystrophy type 2 (DM2) remains uncertain. Here, we aimed at investigating whether there is a parent-of-origin effect on the age at the first DM2-related clinical manifestation. Methods We identified patients with genetically confirmed DM2 with known parental inheritance from (1) the electronic medical records of our institutions and (2) a systematic review of the literature following the PRISMA 2020 guidelines and recorded their age at and type of first disease-related symptom. We also interrogated the Myotonic Dystrophy Foundation Family Registry (MDFFR) for patients with DM2 who completed a survey including questions about parental inheritance and age at the first medical problem which they related to their DM2 diagnosis. Results A total of 26 patients with DM2 from 18 families were identified at our institutions as having maternal (n = 14) or paternal (n = 12) inheritance of the disease, whereas our systematic review of the literature rendered a total of 61 patients with DM2 from 41 families reported by 24 eligible articles as having maternal (n = 40) or paternal (n = 21) inheritance of the disease. Both cohorts were combined for downstream analyses. Up to 61% and 58% of patients had muscle-related symptoms as the first disease manifestation in maternally and paternally inherited DM2 subgroups, respectively. Four patients developed hypotonia at birth and/or delayed motor milestones early in life, and 7 had nonmuscular presentations (2 had cardiac events within the second decade of life and 5 had cataracts), all of them with maternal inheritance. A maternal inheritance was associated with an earlier (within the first 3 decades of life) age at symptom onset relative to a paternal inheritance in this combined cohort, and this association was independent of the patient's sex (OR [95% CI] = 4.245 [1.429-13.820], p = 0.0117). However, this association was not observed in the MDFFR DM2 cohort (n = 127), possibly because age at onset was self-reported, and the information about the type of first symptom or medical problem that patients related to DM2 was lacking. Discussion A maternal inheritance may increase the risk of an early DM2 onset and of cataracts and cardiovascular events as first DM2 manifestations.
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Affiliation(s)
- Paloma Gonzalez-Perez
- Department of Neurology (P.G.-P., V.P.-M., K.C., W.S.D.), Massachusetts General Hospital, Harvard Medical School, Boston, MA; Department of Neurology (E.S.D.A.), Nationwide Children's Hospital, Columbus, OH; and Department of Neurology (V.P.-M., A.A.A.), Brigham Women's Hospital, Harvard Medical School, Boston, MA
| | - Eleonora S D'Ambrosio
- Department of Neurology (P.G.-P., V.P.-M., K.C., W.S.D.), Massachusetts General Hospital, Harvard Medical School, Boston, MA; Department of Neurology (E.S.D.A.), Nationwide Children's Hospital, Columbus, OH; and Department of Neurology (V.P.-M., A.A.A.), Brigham Women's Hospital, Harvard Medical School, Boston, MA
| | - Vincent Picher-Martel
- Department of Neurology (P.G.-P., V.P.-M., K.C., W.S.D.), Massachusetts General Hospital, Harvard Medical School, Boston, MA; Department of Neurology (E.S.D.A.), Nationwide Children's Hospital, Columbus, OH; and Department of Neurology (V.P.-M., A.A.A.), Brigham Women's Hospital, Harvard Medical School, Boston, MA
| | - Kathy Chuang
- Department of Neurology (P.G.-P., V.P.-M., K.C., W.S.D.), Massachusetts General Hospital, Harvard Medical School, Boston, MA; Department of Neurology (E.S.D.A.), Nationwide Children's Hospital, Columbus, OH; and Department of Neurology (V.P.-M., A.A.A.), Brigham Women's Hospital, Harvard Medical School, Boston, MA
| | - William S David
- Department of Neurology (P.G.-P., V.P.-M., K.C., W.S.D.), Massachusetts General Hospital, Harvard Medical School, Boston, MA; Department of Neurology (E.S.D.A.), Nationwide Children's Hospital, Columbus, OH; and Department of Neurology (V.P.-M., A.A.A.), Brigham Women's Hospital, Harvard Medical School, Boston, MA
| | - Anthony A Amato
- Department of Neurology (P.G.-P., V.P.-M., K.C., W.S.D.), Massachusetts General Hospital, Harvard Medical School, Boston, MA; Department of Neurology (E.S.D.A.), Nationwide Children's Hospital, Columbus, OH; and Department of Neurology (V.P.-M., A.A.A.), Brigham Women's Hospital, Harvard Medical School, Boston, MA
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2
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Vivekanandam V, Jayaseelan D, Hanna MG. Muscle channelopathies. HANDBOOK OF CLINICAL NEUROLOGY 2023; 195:521-532. [PMID: 37562884 DOI: 10.1016/b978-0-323-98818-6.00006-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/12/2023]
Abstract
Muscle channelopathies encompass a wide range of mainly episodic conditions that are characterized by muscle stiffness and weakness. The myotonic conditions, characterized predominantly by stiffness, include myotonia congenita, paramyotonia congenita, and sodium channel myotonia. The periodic paralysis conditions include hypokalemic periodic paralysis, hyperkalemic periodic paralysis, and Andersen-Tawil syndrome. Clinical history is key, and diagnosis is confirmed by next-generation genetic sequencing of a panel of known genes but can also be supplemented by neurophysiology studies and MRI. As genetic testing expands, so have the spectrum of phenotypes seen including pediatric presentations and congenital myopathies. Management of these conditions requires a multidisciplinary approach with extra support needed when patients require anesthetics or when pregnant. Patients with Andersen-Tawil syndrome will also need cardiac input. Diagnosis is important as symptomatic treatment is available for all of these conditions but need to be tailored to the gene and variant of the patient.
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Affiliation(s)
- Vinojini Vivekanandam
- Centre for Neuromuscular Disorders, Queen Square UCL Institute of Neurology, London, United Kingdom
| | | | - Michael G Hanna
- Centre for Neuromuscular Disorders, Queen Square UCL Institute of Neurology, London, United Kingdom.
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3
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Meng YX, Yu M, Liu C, Zhang H, Yang Y, Zhang J. Sequence CLCN1 and SCN4A genes in patients with nondystrophic myotonia in Chinese people. Medicine (Baltimore) 2022; 101:e29591. [PMID: 35866763 PMCID: PMC9302320 DOI: 10.1097/md.0000000000029591] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
BACKGROUND This study aimed to characterize the genetic, pathological, and clinical alterations of 17 patients in China presenting with nondystrophic myotonia (NDM) and to analyze the relationship between genotype and clinical phenotype. METHODS CLCN1 and SCN4A genes in patients with clinical features and muscle pathology indicative of NDM were sequenced. Furthermore, KCNE3 and CACNA1S genes were assessed in patients with wild-type CLCN1 and SCN4A. RESULTS Patients may have accompanying atypical myopathy as well as muscle hypertrophy, secondary dystonia, and joint contracture as determined by needle electromyography. All the study participants were administered mexiletine in combination with carbamazepine and showed significant improvements in myotonia symptoms in response to this therapy. CLCN1 gene mutation was detected in 8 cases diagnosed with myotonia congenital using gene screening. The detected mutations included 5 missense, 2 nonsense, 1 deletion, and 2 insertions. Further gene analysis showed 4 mutations in the SCN4A gene in patients diagnosed with paramyotonia congenita. CONCLUSIONS Myotonia congenita and paramyotonia congenita are the predominant forms of NDM in China. NDM may be best diagnosed using genetic analysis in associated with clinical features.
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Affiliation(s)
- Yan-Xin Meng
- Department of prenatal diagnostic center, Shijiazhuang gynaecology and obstertrics Hospital, Key Laboratory of Maternal and Fetal Medicine of Hebei Province, Hebei, Shijiazhuang, P.R. China
| | - Mei Yu
- Department of prenatal diagnostic center, Shijiazhuang gynaecology and obstertrics Hospital, Key Laboratory of Maternal and Fetal Medicine of Hebei Province, Hebei, Shijiazhuang, P.R. China
| | - Chunmiao Liu
- Department of obstetrics and gynecology, Shijiazhuang gynaecology and obstertrics Hospital, Hebei, Shijiazhuang, P.R. China
| | - Haijuan Zhang
- Department of obstetrics and gynecology, Shijiazhuang gynaecology and obstertrics Hospital, Hebei, Shijiazhuang, P.R. China
| | - Yuxiu Yang
- Department of obstetrics and gynecology, Shijiazhuang gynaecology and obstertrics Hospital, Hebei, Shijiazhuang, P.R. China
- *Correspondence: Jing Zhang, Department of prenatal diagnostic center, Shijiazhuang gynaecology and obstertrics Hospital, Hebei, Shijiazhuang 050071, P.R. China (e-mail: )
| | - Jing Zhang
- Department of prenatal diagnostic center, Shijiazhuang gynaecology and obstertrics Hospital, Key Laboratory of Maternal and Fetal Medicine of Hebei Province, Hebei, Shijiazhuang, P.R. China
- *Correspondence: Jing Zhang, Department of prenatal diagnostic center, Shijiazhuang gynaecology and obstertrics Hospital, Hebei, Shijiazhuang 050071, P.R. China (e-mail: )
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Suetterlin K, Matthews E, Sud R, McCall S, Fialho D, Burge J, Jayaseelan D, Haworth A, Sweeney MG, Kullmann DM, Schorge S, Hanna MG, Männikkö R. Translating genetic and functional data into clinical practice: a series of 223 families with myotonia. Brain 2022; 145:607-620. [PMID: 34529042 PMCID: PMC9014745 DOI: 10.1093/brain/awab344] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Revised: 07/13/2021] [Accepted: 08/05/2021] [Indexed: 11/14/2022] Open
Abstract
High-throughput DNA sequencing is increasingly employed to diagnose single gene neurological and neuromuscular disorders. Large volumes of data present new challenges in data interpretation and its useful translation into clinical and genetic counselling for families. Even when a plausible gene is identified with confidence, interpretation of the clinical significance and inheritance pattern of variants can be challenging. We report our approach to evaluating variants in the skeletal muscle chloride channel ClC-1 identified in 223 probands with myotonia congenita as an example of these challenges. Sequencing of CLCN1, the gene that encodes CLC-1, is central to the diagnosis of myotonia congenita. However, interpreting the pathogenicity and inheritance pattern of novel variants is notoriously difficult as both dominant and recessive mutations are reported throughout the channel sequence, ClC-1 structure-function is poorly understood and significant intra- and interfamilial variability in phenotype is reported. Heterologous expression systems to study functional consequences of CIC-1 variants are widely reported to aid the assessment of pathogenicity and inheritance pattern. However, heterogeneity of reported analyses does not allow for the systematic correlation of available functional and genetic data. We report the systematic evaluation of 95 CIC-1 variants in 223 probands, the largest reported patient cohort, in which we apply standardized functional analyses and correlate this with clinical assessment and inheritance pattern. Such correlation is important to determine whether functional data improves the accuracy of variant interpretation and likely mode of inheritance. Our data provide an evidence-based approach that functional characterization of ClC-1 variants improves clinical interpretation of their pathogenicity and inheritance pattern, and serve as reference for 34 previously unreported and 28 previously uncharacterized CLCN1 variants. In addition, we identify novel pathogenic mechanisms and find that variants that alter voltage dependence of activation cluster in the first half of the transmembrane domains and variants that yield no currents cluster in the second half of the transmembrane domain. None of the variants in the intracellular domains were associated with dominant functional features or dominant inheritance pattern of myotonia congenita. Our data help provide an initial estimate of the anticipated inheritance pattern based on the location of a novel variant and shows that systematic functional characterization can significantly refine the assessment of risk of an associated inheritance pattern and consequently the clinical and genetic counselling.
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Affiliation(s)
- Karen Suetterlin
- MRC International Centre for Genomic Medicine in Neuromuscular Diseases, Department of Neuromuscular Disease, UCL Queen Square Institute of Neurology, London, UK
- AGE Research Group, NIHR Newcastle Biomedical Research Centre, Newcastle-upon-Tyne Hospitals NHS Foundation Trust and Newcastle University, Newcastle-upon-Tyne, UK
| | - Emma Matthews
- MRC International Centre for Genomic Medicine in Neuromuscular Diseases, Department of Neuromuscular Disease, UCL Queen Square Institute of Neurology, London, UK
- Atkinson Morley Neuromuscular Centre, Department of Neurology, St Georges University Hospitals NHS Foundation Trust, London, UK
| | - Richa Sud
- Neurogenetics Unit, UCL Queen Square Institute of Neurology, London, UK
| | - Samuel McCall
- Neurogenetics Unit, UCL Queen Square Institute of Neurology, London, UK
| | - Doreen Fialho
- MRC International Centre for Genomic Medicine in Neuromuscular Diseases, Department of Neuromuscular Disease, UCL Queen Square Institute of Neurology, London, UK
- Department of Clinical Neurophysiology, King’s College Hospital, London, UK
| | - James Burge
- MRC International Centre for Genomic Medicine in Neuromuscular Diseases, Department of Neuromuscular Disease, UCL Queen Square Institute of Neurology, London, UK
- Department of Clinical Neurophysiology, King’s College Hospital, London, UK
| | - Dipa Jayaseelan
- MRC International Centre for Genomic Medicine in Neuromuscular Diseases, Department of Neuromuscular Disease, UCL Queen Square Institute of Neurology, London, UK
| | - Andrea Haworth
- Neurogenetics Unit, UCL Queen Square Institute of Neurology, London, UK
| | - Mary G Sweeney
- Neurogenetics Unit, UCL Queen Square Institute of Neurology, London, UK
| | - Dimitri M Kullmann
- Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London, UK
| | - Stephanie Schorge
- Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London, UK
- Department of Pharmacology, UCL School of Pharmacy, London, UK
| | - Michael G Hanna
- MRC International Centre for Genomic Medicine in Neuromuscular Diseases, Department of Neuromuscular Disease, UCL Queen Square Institute of Neurology, London, UK
| | - Roope Männikkö
- MRC International Centre for Genomic Medicine in Neuromuscular Diseases, Department of Neuromuscular Disease, UCL Queen Square Institute of Neurology, London, UK
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5
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Hanoun S, Sun Y, Ebrahimi F, Ghasemi M. Speech and language abnormalities in myotonic dystrophy: An overview. J Clin Neurosci 2021; 96:212-220. [PMID: 34789418 DOI: 10.1016/j.jocn.2021.10.031] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2021] [Revised: 09/30/2021] [Accepted: 10/24/2021] [Indexed: 12/26/2022]
Abstract
Myotonic dystrophy (DM) is an autosomal dominant neuromuscular and multisystem disease that is divided into two types, DM1 and DM2, according to mutations in DMPK and CNBP genes, respectively. DM patients may manifest with various speech and language abnormalities. In this review, we had an overview on speech and language abnormalities in both DM1 and DM2. Our literature search highlights that irrespective of age, all DM patients (i.e. congenital, juvenile, and adult onset DM1 as well as DM2 patients) exhibit various degrees of speech impairments. These problems are related to both cognitive dysfunction (e.g. difficulties in written and spoken language) and bulbar/vocal muscles weakness and myotonia. DM1 adult patients have also a significant decrease in speech rate and performance due to myotonia and flaccid dysarthria, which can improve with warming up. Weakness, tiredness, and hypotonia of oral and velopharyngeal muscles can cause flaccid dysarthria. Hearing impairment also plays a role in affecting speech recognition in DM2. A better understanding of different aspects of speech and language abnormalities in DM patients may provide better characterization of these abnormalities as markers that can be potentially used as outcome measures in natural history studies or clinical trials.
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Affiliation(s)
- Sakhaa Hanoun
- Department of Neurology, University of Massachusetts Medical School, Worcester, MA 01655, USA; Department of Medicine, Al-Quds University, Jerusalem, Palestine
| | - Yuyao Sun
- Department of Neurology, University of Massachusetts Medical School, Worcester, MA 01655, USA
| | - Farzad Ebrahimi
- Department of Anesthesiology, University of Illinois at Chicago, Chicago, IL, USA; Department of Anesthesiology, Advocate Illinois Masonic Medical Center, Chicago, IL, USA
| | - Mehdi Ghasemi
- Department of Neurology, University of Massachusetts Medical School, Worcester, MA 01655, USA.
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6
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Botta A, Visconti VV, Fontana L, Bisceglia P, Bengala M, Massa R, Bagni I, Cardani R, Sangiuolo F, Meola G, Antonini G, Petrucci A, Pegoraro E, D'Apice MR, Novelli G. A 14-Year Italian Experience in DM2 Genetic Testing: Frequency and Distribution of Normal and Premutated CNBP Alleles. Front Genet 2021; 12:668094. [PMID: 34234810 PMCID: PMC8255792 DOI: 10.3389/fgene.2021.668094] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Accepted: 05/05/2021] [Indexed: 11/16/2022] Open
Abstract
Myotonic dystrophy type 2 (DM2) is a multisystemic disorder caused by a (CCTG)n in intron 1 of the CNBP gene. The CCTG repeat tract is part of a complex (TG)v(TCTG)w(CCTG)x(NCTG)y(CCTG)z motif generally interrupted in CNBP healthy range alleles. Here we report our 14-year experience of DM2 postnatal genetic testing in a total of 570 individuals. The DM2 locus has been analyzed by a combination of SR-PCR, TP-PCR, LR-PCR, and Sanger sequencing of CNBP alleles. DM2 molecular diagnosis has been confirmed in 187/570 samples analyzed (32.8%) and is mainly associated with the presence of myotonia in patients. This set of CNBP alleles showed unimodal distribution with 25 different alleles ranging from 108 to 168 bp, in accordance with previous studies on European populations. The most frequent CNBP alleles consisted of 138, 134, 140, and 136 bps with an overall locus heterozygosity of 90%. Sequencing of 103 unexpanded CNBP alleles in DM2-positive patients revealed that (CCTG)5(NCTG)3(CCTG)7 and (CCTG)6(NCTG)3(CCTG)7 are the most common interruption motifs. We also characterized five CNBP premutated alleles with (CCTG)n repetitions from n = 36 to n = 53. However, the molecular and clinical consequences in our cohort of samples are not unequivocal. Data that emerged from this study are representative of the Italian population and are useful tools for National and European centers offering DM2 genetic testing and counseling.
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Affiliation(s)
- Annalisa Botta
- Medical Genetics Section, Department of Biomedicine and Prevention, University of Rome Tor Vergata, Rome, Italy
| | - Virginia Veronica Visconti
- Medical Genetics Section, Department of Biomedicine and Prevention, University of Rome Tor Vergata, Rome, Italy
| | - Luana Fontana
- Medical Genetics Section, Department of Biomedicine and Prevention, University of Rome Tor Vergata, Rome, Italy
| | - Paola Bisceglia
- Laboratory of Medical Genetics, Tor Vergata Hospital, Rome, Italy.,Research Laboratory, Complex Structure of Geriatrics, Fondazione IRCCS Casa Sollievo della Sofferenza, San Giovanni Rotondo, Italy
| | - Mario Bengala
- Laboratory of Medical Genetics, Tor Vergata Hospital, Rome, Italy
| | - Roberto Massa
- Neuromuscular Disease Unit, Department of Systems Medicine, University of Rome Tor Vergata, Rome, Italy
| | - Ilaria Bagni
- Laboratory of Medical Genetics, Tor Vergata Hospital, Rome, Italy
| | - Rosanna Cardani
- BioCor Biobank, UOC SMEL-1 of Clinical Pathology, IRCCS-Policlinico San Donato, Milan, Italy
| | - Federica Sangiuolo
- Medical Genetics Section, Department of Biomedicine and Prevention, University of Rome Tor Vergata, Rome, Italy.,Laboratory of Medical Genetics, Tor Vergata Hospital, Rome, Italy
| | - Giovanni Meola
- Department of Biomedical Sciences for Health, University of Milan, Milan, Italy.,Department of Neurorehabilitation Sciences, Casa di Cura del Policlinico, Milan, Italy
| | - Giovanni Antonini
- Neuromuscular and Rare Disease Center, Department of Neuroscience, Mental Health and Sensory Organs (NESMOS), Sant'Andrea Hospital, Sapienza University of Rome, Rome, Italy
| | - Antonio Petrucci
- Center for Neuromuscular and Neurological Rare Diseases, S. Camillo Forlanini Hospital, Rome, Italy
| | - Elena Pegoraro
- Department of Neuroscience, University of Padua, Padua, Italy
| | | | - Giuseppe Novelli
- Medical Genetics Section, Department of Biomedicine and Prevention, University of Rome Tor Vergata, Rome, Italy.,Laboratory of Medical Genetics, Tor Vergata Hospital, Rome, Italy
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7
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Desaphy JF, Altamura C, Vicart S, Fontaine B. Targeted Therapies for Skeletal Muscle Ion Channelopathies: Systematic Review and Steps Towards Precision Medicine. J Neuromuscul Dis 2021; 8:357-381. [PMID: 33325393 PMCID: PMC8203248 DOI: 10.3233/jnd-200582] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
BACKGROUND Skeletal muscle ion channelopathies include non-dystrophic myotonias (NDM), periodic paralyses (PP), congenital myasthenic syndrome, and recently identified congenital myopathies. The treatment of these diseases is mainly symptomatic, aimed at reducing muscle excitability in NDM or modifying triggers of attacks in PP. OBJECTIVE This systematic review collected the evidences regarding effects of pharmacological treatment on muscle ion channelopathies, focusing on the possible link between treatments and genetic background. METHODS We searched databases for randomized clinical trials (RCT) and other human studies reporting pharmacological treatments. Preclinical studies were considered to gain further information regarding mutation-dependent drug effects. All steps were performed by two independent investigators, while two others critically reviewed the entire process. RESULTS For NMD, RCT showed therapeutic benefits of mexiletine and lamotrigine, while other human studies suggest some efficacy of various sodium channel blockers and of the carbonic anhydrase inhibitor (CAI) acetazolamide. Preclinical studies suggest that mutations may alter sensitivity of the channel to sodium channel blockers in vitro, which has been translated to humans in some cases. For hyperkalemic and hypokalemic PP, RCT showed efficacy of the CAI dichlorphenamide in preventing paralysis. However, hypokalemic PP patients carrying sodium channel mutations may have fewer benefits from CAI compared to those carrying calcium channel mutations. Few data are available for treatment of congenital myopathies. CONCLUSIONS These studies provided limited information about the response to treatments of individual mutations or groups of mutations. A major effort is needed to perform human studies for designing a mutation-driven precision medicine in muscle ion channelopathies.
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Affiliation(s)
- Jean-François Desaphy
- Department of Biomedical Sciences and Human Oncology, School of Medicine, University of Bari Aldo Moro, Bari, Italy
| | - Concetta Altamura
- Department of Biomedical Sciences and Human Oncology, School of Medicine, University of Bari Aldo Moro, Bari, Italy
| | - Savine Vicart
- Sorbonne Université, INSERM, Assistance Publique Hôpitaux de Paris, Centre de Recherche en Myologie-UMR 974, Reference center in neuro-muscular channelopathies, Institute of Myology, Hôpital Universitaire Pitié-Salpêtrière, Paris, France
| | - Bertrand Fontaine
- Sorbonne Université, INSERM, Assistance Publique Hôpitaux de Paris, Centre de Recherche en Myologie-UMR 974, Reference center in neuro-muscular channelopathies, Institute of Myology, Hôpital Universitaire Pitié-Salpêtrière, Paris, France
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8
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Meola G. Myotonic dystrophy type 2: the 2020 update. ACTA MYOLOGICA : MYOPATHIES AND CARDIOMYOPATHIES : OFFICIAL JOURNAL OF THE MEDITERRANEAN SOCIETY OF MYOLOGY 2020; 39:222-234. [PMID: 33458578 PMCID: PMC7783423 DOI: 10.36185/2532-1900-026] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Accepted: 11/09/2020] [Indexed: 12/26/2022]
Abstract
The myotonic dystrophies are the commonest cause of adult-onset muscular dystrophy. Phenotypes of DM1 and DM2 are similar, but there are some important differences, including the presence or absence of congenital form, muscles primarily affected (distal vs proximal), involved muscle fiber types (type 1 vs type 2 fibers), and some associated multisystemic phenotypes. There is currently no cure for the myotonic dystrophies but effective management significantly reduces the morbidity and mortality of patients. For the enormous understanding of the molecular pathogenesis of myotonic dystrophy type 1 and myotonic dystrophy type 2, these diseases are now called "spliceopathies" and are mediated by a primary disorder of RNA rather than proteins. Despite clinical and genetic similarities, myotonic dystrophy type 1 and type 2 are distinct disorders requiring different diagnostic and management strategies. Gene therapy for myotonic dystrophy type 1 and myotonic dystrophy type 2 appears to be very close and the near future is an exciting time for clinicians and patients.
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Affiliation(s)
- Giovanni Meola
- Department of Biomedical Sciences for Health, University of Milan, Italy.,Department of Neurorehabilitation Sciences, Casa di Cura del Policlinico, Milan, Italy
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9
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Vivekanandam V, Männikkö R, Matthews E, Hanna MG. Improving genetic diagnostics of skeletal muscle channelopathies. Expert Rev Mol Diagn 2020; 20:725-736. [PMID: 32657178 DOI: 10.1080/14737159.2020.1782195] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
INTRODUCTION Skeletal muscle channelopathies are rare inherited conditions that cause significant morbidity and impact on quality of life. Some subsets have a mortality risk. Improved genetic methodology and understanding of phenotypes have improved diagnostic accuracy and yield. AREAS COVERED We discuss diagnostic advances since the advent of next-generation sequencing and the role of whole exome and genome sequencing. Advances in genotype-phenotype-functional correlations have improved understanding of inheritance and phenotypes. We outline new phenotypes, particularly in the pediatric setting and consider co-existing mutations that may act as genetic modifiers. We also discuss four newly identified genes associated with skeletal muscle channelopathies. EXPERT OPINION Next-generation sequencing using gene panels has improved diagnostic rates, identified new mutations, and discovered patients with co-existing pathogenic mutations ('double trouble'). This field has previously focussed on single genes, but we are now beginning to understand interactions between co-existing mutations, genetic modifiers, and their role in pathomechanisms. New genetic observations in pediatric presentations of channelopathies broadens our understanding of the conditions. Genetic and mechanistic advances have increased the potential to develop treatments.
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Affiliation(s)
- Vinojini Vivekanandam
- Queen Square Centre for Neuromuscular Diseases and Department of Neuromuscular Diseases, Queen Square Institute of Neurology, UCL and National Hospital for Neurology and Neurosurgery , London, UK
| | - Roope Männikkö
- Queen Square Centre for Neuromuscular Diseases and Department of Neuromuscular Diseases, Queen Square Institute of Neurology, UCL and National Hospital for Neurology and Neurosurgery , London, UK
| | - Emma Matthews
- Queen Square Centre for Neuromuscular Diseases and Department of Neuromuscular Diseases, Queen Square Institute of Neurology, UCL and National Hospital for Neurology and Neurosurgery , London, UK
| | - Michael G Hanna
- Queen Square Centre for Neuromuscular Diseases and Department of Neuromuscular Diseases, Queen Square Institute of Neurology, UCL and National Hospital for Neurology and Neurosurgery , London, UK
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10
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Wansink DG, Gourdon G, van Engelen BGM, Schoser B. 248th ENMC International Workshop: Myotonic dystrophies: Molecular approaches for clinical purposes, framing a European molecular research network, Hoofddorp, the Netherlands, 11-13 October 2019. Neuromuscul Disord 2020; 30:521-531. [PMID: 32417002 DOI: 10.1016/j.nmd.2020.03.011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Accepted: 03/19/2020] [Indexed: 01/11/2023]
Affiliation(s)
- Derick G Wansink
- Radboud Institute for Molecular Life Sciences, Department of Cell Biology, Radboud University Medical Center, 6525 GA Nijmegen, the Netherlands
| | - Geneviève Gourdon
- Inserm UMR 974, Sorbonne Université, Centre de Recherche en Myologie, Association Institut de Myologie, 75013 Paris, France
| | - Baziel G M van Engelen
- Donders Institute for Brain, Cognition and Behaviour, Department of Neurology, Radboud University Medical Center, 6525 GC Nijmegen, the Netherlands
| | - Benedikt Schoser
- Friedrich-Baur-Institute, Department of Neurology, Ludwig-Maximilians-University, Munich, Germany.
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Bozovic I, Peric S, Pesovic J, Bjelica B, Brkusanin M, Basta I, Bozic M, Sencanic I, Marjanovic A, Brankovic M, Savic-Pavicevic D, Rakocevic-Stojanovic V. Myotonic Dystrophy Type 2 – Data from the Serbian Registry. J Neuromuscul Dis 2018; 5:461-469. [DOI: 10.3233/jnd-180328] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Affiliation(s)
- Ivo Bozovic
- Neurology Clinic, Clinical Center of Serbia, School of Medicine, University of Belgrade, Belgrade, Serbia
| | - Stojan Peric
- Neurology Clinic, Clinical Center of Serbia, School of Medicine, University of Belgrade, Belgrade, Serbia
| | - Jovan Pesovic
- Faculty of Biology, Center for Human Molecular Genetics, University of Belgrade, Belgrade, Serbia
| | - Bogdan Bjelica
- Neurology Clinic, Clinical Center of Serbia, School of Medicine, University of Belgrade, Belgrade, Serbia
| | - Milos Brkusanin
- Faculty of Biology, Center for Human Molecular Genetics, University of Belgrade, Belgrade, Serbia
| | - Ivana Basta
- Neurology Clinic, Clinical Center of Serbia, School of Medicine, University of Belgrade, Belgrade, Serbia
| | - Marija Bozic
- Ophthalmology Clinic, Clinical Center of Serbia, School of Medicine, University of Belgrade, Belgrade, Serbia
| | - Ivan Sencanic
- Ophthalmology Clinic, Clinical Center Zvezdara, Belgrade, Serbia
| | - Ana Marjanovic
- Neurology Clinic, Clinical Center of Serbia, School of Medicine, University of Belgrade, Belgrade, Serbia
| | - Marija Brankovic
- Neurology Clinic, Clinical Center of Serbia, School of Medicine, University of Belgrade, Belgrade, Serbia
| | - Dusanka Savic-Pavicevic
- Faculty of Biology, Center for Human Molecular Genetics, University of Belgrade, Belgrade, Serbia
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Abstract
Myotonic dystrophy is an autosomal dominant muscular dystrophy not only associated with muscle weakness, atrophy, and myotonia but also prominent multisystem involvement. There are 2 similar, but distinct, forms of myotonic dystrophy; type 1 is caused by a CTG repeat expansion in the DMPK gene, and type 2 is caused by a CCTG repeat expansion in the CNBP gene. Type 1 is associated with distal limb, neck flexor, and bulbar weakness and results in different phenotypic subtypes with variable onset from congenital to very late-onset as well as variable signs and symptoms. The classically described adult-onset form is the most common. In contrast, myotonic dystrophy type 2 is adult-onset or late-onset, has proximal predominant muscle weakness, and generally has less severe multisystem involvement. In both forms of myotonic dystrophy, the best characterized disease mechanism is a RNA toxic gain-of-function during which RNA repeats form nuclear foci resulting in sequestration of RNA-binding proteins and, therefore, dysregulated splicing of premessenger RNA. There are currently no disease-modifying therapies, but clinical surveillance, preventative measures, and supportive treatments are used to reduce the impact of muscular impairment and other systemic involvement including cataracts, cardiac conduction abnormalities, fatigue, central nervous system dysfunction, respiratory weakness, dysphagia, and endocrine dysfunction. Exciting preclinical progress has been made in identifying a number of potential strategies including genome editing, small molecule therapeutics, and antisense oligonucleotide-based therapies to target the pathogenesis of type 1 and type 2 myotonic dystrophies at the DNA, RNA, or downstream target level.
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Affiliation(s)
- Samantha LoRusso
- Department of Neurology, The Ohio State University, 395 West 12th Avenue, Columbus, OH, 43210, USA
| | - Benjamin Weiner
- The Ohio State University College of Medicine, The Ohio State University, 370 West 9th Avenue, Columbus, OH, 43210, USA
| | - W David Arnold
- Department of Neurology, The Ohio State University, 395 West 12th Avenue, Columbus, OH, 43210, USA.
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